The Chink in the Armour by Marie Belloc Lowndes

On the morning after her visit to Madame Cagliostra, Sylvia Bailey woke later than usual. She had had a disturbed night, and it was pleasant to feel that she could spend a long restful day doing nothing, or only taking part in one of the gay little expeditions which make Paris to a stranger the most delightful of European capitals.

She opened wide both the windows of her room, and from outside there floated in a busy, happy murmur, for Paris is an early city, and nine o'clock there is equivalent to eleven o'clock in London.